1. Field of the Invention
The invention concerns a process and a device for application of active substances to a wound surface.
2. Description of the Related Art
For the medicinal local treatment of wounds there have until now been employed salves, solutions or solid medicament carriers, such as resorbable collagen, antibiotic soaked bone cement or impregnated wound coverings. In particular in deep wounds there exists the difficulty, that salves are not employable, and solutions are soaked up by bandage materials and frequently do not come into sufficient contact with the inner wound surface, in order that its therapeutic effect unfolds. In the implantation of foreign body medicinal carriers, such as bone cement or resorbable materials, there occurs a loss of effectiveness by dissipation or dilution with wound secretion. Besides this only a few medicines are available, which exhibit a local sustained effect over a long period of time. In the tissue, under certain conditions, a damaging or injurious reaction to the foreign body can result. Decomposable medicine carriers can, in their decomposition, lead to undesirable side effects.
From DE 40 12 232 A1 there is disclosed a Redon-bandage or, as the case may be, installation-bandage for the treatment of superficial and deep problematic wounds, in particular with infections, in which the wound is covered by a thin semi-permeable foil. A supply line and a removal line are provided under the foil in the wound area. Active substances can be applied to the wound surface under the foil via the supply line by means of a syringe. After the desired application period the active substances can, in certain cases together with the wound secretion, be suctioned out via the removal line by means of a vacuum source. The supply line is provided with a self-acting closing safety valve, which is opened by the introduced syringe for introduction of the fluid active substances. Likewise there is provided on the removal line a closure or blockage mechanism, which closes off the output side during the application period of the active substance.
In this known installation bandage the active substances are applied directly upon the wound surface and suctioned off from the wound surface. The active substance can thus only be applied in imprecise doses and in particular in the case of large wound surface areas an even effect upon the entire surface is difficult to achieve. A long time continuous effect can not realized.
From U.S. Pat. No. 4,382,441 it is known, for treatment of wound surfaces, to lay a padding or dressing made of a porous material upon the wound surface and to sealingly cover this. The active substance to be applied is continuously conveyed through the padding, for which a fluid supply connection and a fluid removal connection communicate with the padding. The capillary effect of the porous padding optimizes the distribution of the supplied active substance over the entirety of the surface of the padding in contact with the wound surface.
The porous padding is substantially form-stable and also the sealing cover is preferably form-stable. The fluid active substance is conveyed through the padding in a continuous stream, whereby a stream distribution results, in which the fluid active substance flows essentially along the area between the fluid supply connection and fluid removal connection, while the edge areas of the padding are barely perfused. Thus, in these edge areas the active substances are only exchanged in small amounts and, further, in the edge areas accumulations of wound secretion are only insufficiently removed. Beyond this the relatively form stable padding does not lie in all areas equally against the wound surface, so that also hereby an even application of the active substance and an even removal of the wound secretion is compromised. A continuous effect is not envisioned or intended.